Embodiments herein generally relate to printing devices and more particularly to printing devices that use wires or other toner charging devices used to create a cloud of toner during the printing process.
Development housings within electrostatic printing devices can use AC and DC biased wires to launch a toner cloud for non-contact development to a photoreceptor (PR). However, in such systems the wires can sometimes become polluted with toner constituents, thereby decreasing the effectiveness of the cloud.
Some methods of managing wire pollution are based on non-nominal fleet operation data, in which wire cleaning set points are selected based on average or worst-case wire pollution stress conditions. These set points may not be optimal for the non-stress conditions, and the performance of cleaning operations on printing devices that experience non-stress conditions can be wasteful.
For example, a wire cleaning cycle can be performed, which involves pressing the wire against the donor roll to remove pollution on the wire. This can be run at cycle up and cycle down. This routine is used to change the charge and shake the wire, and is a successful method of removing the toner build-up on the wire. This is not currently performed during printing run, because it would cause sudden color shifts during the run. This wire cleaning cycle can cause huge transients in development and causes color shifts if run infrequently. Therefore, this is not a good solution to wire pollution if performed infrequently or mid-job. This method also adds stress to the wire.
Also, a periodic toner purging can be preformed during a “deadcycle” (time of non-usage of a printing device) to decrease toner age and reduce wire contamination. For example, the periodic toner purge can be preformed on every machine in every condition when toner age reaches a threshold. However, for printing machines that are not experiencing wire contamination, this fleet-wide toner purge process can waste time, electricity, and toner. Further, a minimum area coverage (MAC) patch can be used to slow the rate of toner aging in the sump, to reduce wire contamination. Again however, this treats all machines in a fleet equally when it comes to managing toner age, and can be wasteful on printing machines that are not experiencing wire contamination.